[Neutron] J-PARC Newsletter No.48 Apr 2012

Nobuaki TAKAHASHI nobuaki.takahashi at j-parc.jp
Mon Apr 23 11:22:52 CEST 2012


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     J-PARC Project Newsletter
                                         No. 48, Apr. 2012
Japan Proton Accelerator Research Complex under operation jointly
by the High Energy Accelerator Research Organization (KEK) and
the Japan Atomic Energy Agency (JAEA) 
http://j-parc.jp/index-e.html

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HEADLINES AND CONTENTS

1. [Overview]

J-PARC IS RUNNING WELL.
J-PARC REVIEW IN PROGRESS.
INTERNATIONAL ADVISORY COMMITTEE AND OTHER COMMITTEE MEETINGS WERE 
HELD.
RISE IN ELECTRICITY POWER COST ANNOUNCED BY TEPCO.

2. [Accelerator Division]

STATUS OF THE ACCELERATOR FACILITIES: USER SERVICE WAS STARTED.
A-TAC (ACCELERATOR ADVISORY COMMITTEE) MEETING.  

3. [Nuclear and Particle Physics Division]

SLOW EXTRACTION RESUMES AFTER EARTHQUAKE.
T2K STATUS: STABLE DATA TAKING RESTARTED AFTER 1 YEAR OF RECOVERY 
FROM THE EARTHQUAKE.

4. [Materials and Life Science Division]

RESUMING USER OPERATION.
EIGHTEEN NEUTRON INSTRUMENTS INCLUDING SIX NEW ONES HAVE BEEN STARTED.
COMMISSIONING OF NEW DETECTORS.
THE REGULAR USERS' PROGRAM AT MUSE WERE RESTARTED FROM FEB. 2ND, 
2012.

5. [Exotic Nuclear Science Group]

SELECTIVELY IONIZED ATOMS EXTRACTED AT KISS.
CROSS SECTION MEASUREMENTS WERE PERFORMED FOR MULTI-NUCLEON TRANSFER 
REACTIONS.

6. [Nuclear Transmutation Section]

INTERNATIONAL SYMPOSIUM ON FUTURE OF ACCELERATOR DRIVEN SYSTEM WAS 
ORGANIZED.

7. [Safety Division]

THE SAFETY INSPECTIONS OF MLF AND HD WERE SUCCESSFULLY CONDUCTED BY 
NUSTEC.

8. [Announcement of Symposia and Meetings]

9. [Editorial Note]


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1. [Overview] by Shoji NAGAMIYA
----------------------------------------------------------------------
 
 J-PARC IS RUNNING WELL

     A new fiscal year started on April 1st.
     After the recovery from the damage due to the earthquake, the 
J-PARC has been running reasonably well.  In January we had troubles 
in the power supply for the neutrino horn (horn = focusing device to 
narrow down the pion beam toward Super-Kamiokande).  At the end of 
March we had another trouble in the power supply for klystrons at an 
early stage of Linac and this trouble created shutdown of the entire 
beams for over a week.  It was recovered by swithcing a power supply.
     Otherwise, we had a smooth running for user operation.  Both 
neutron and muon took data.  Hadron also took data while the neutrino 
program was off.  In addition, the neutrino group started to take 
data from March and they added statistics.
     In JFY2012 we plan to run user programs up to about 180 days.

 J-PARC REVIEW IN PROGRESS

     The Government started their review of J-PARC on March 7, 2012.
At the first meeting, the status of the J-PARC was reported.  Also, 
many discussions were held on how to proceed with reviews of the 
entire project.
     In April there are two review meetings.  Here, 1) the 
organization for the J-PARC operation, 2) internationalization, and 
3) future scope of all facilities will be reviewed.  A particular 
emphasis is the point 3).  The review of materials and life science 
is planned at the first meeting and other reviews on accelerator, 
hadron, neutrino, and nuclear transmutation will be held at the 
second meeting in April.  In May, two meetings are also planned.  
At the first meeting in May, all future plans will be discussed and 
prioritized.  At the second meeting in May the writing of the 
recommendations will be discussed.
     The chair of the review committee is Professor Hide Fukuyama.

 INTERNATIONAL ADVISORY COMMITTEE AND OTHER COMMITTEE MEETINGS WERE 
HELD
 
     The International Advisory Committee (Chair: Jean-Michel
Poutissou) was held on February 27 and 28.  Prior to this meeting, 
Neutron Advisory Committee (Chair: Uschi Steigenberger) and Muon 
Advisory Committee (Chair: Elvezio Morenzon) were held in early to 
middle of February.  All committees discussed seriously the present 
performance as well as future prospects of J-PARC.  Reports are 
being prepared.
     Also, on March 16-18 the Particle and Nuclear Physics PAC was 
held.  The discussion at this time focused on the future five year 
plan in both particle physics and nuclear physics.  Results will be 
presented at the Review Committee by the Government.

 RISE IN ELECTRICITY POWER COST ANNOUNCED BY TEPCO

     The TEPCO announced a large (about 30%) increase for J-PARC 
electricity bill from JFY2014.  We are very disappointed with it and 
will have a negotiation with TEPCO and the Government.


----------------------------------------------------------------------
2. [Accelerator Division] by Kazuo HASEGAWA
----------------------------------------------------------------------

 STATUS OF THE ACCELERATOR FACILITIES: USER SERVICE WAS STARTED

     In December 2011, operations were low duty such as single-shots 
or 1 to 2.5 Hz for beam tuning at the linac, the 3 GeV rapid cycling 
synchrotron (RCS), the Materials and Life Science Experimental 
Facility (MLF), the Main Ring (MR) and the Neutrino Experimental 
Facility (NU). 
     At the beginning of January 2012, we started beam tuning at the 
full repetition rate of 25 Hz at the linac and the RCS. During the 
tuning, we performed the 300 kW test from the RCS and confirmed that 
we could increase the power when the neutron target would be ready. 
After the tuning, the user program of the MLF and the NU started at 
120kW and 60 to 87 kW, respectively. 
     In February, since a power supply for the electromagnetic horn 
at the NU broke down, the beam from the MR was tuned and delivered to 
the Hadron Experimental Facility (HD). As a result of the tuning, 
beam power of 10 kW was attained in the demonstration, and beam of 
3.3 kW with duty factor of 30 % was delivered to the hadron users 
successfully.
     At the start-up after the maintenance period in February, the 
beam current from the linac was increased from 15 to 20 mA and a 420 
kW tuning with the RCS was carried out. This condition was also 
performed in January 2011, and the impact of misalignment of the RCS 
magnets due to the earthquake was examined. As a result, by adjusting 
the operating parameters of the RCS, we can reduce beam loss in the 
RCS and in the downstream beam transport line. The beam loss is still 
higher than that before the earthquake, but the amount is at an
acceptable level.
     Therefore, we decided to perform realignment of the RCS magnets, 
which will take several months, in the summer of 2013 according to 
the shutdown for an energy upgrade of the linac.
     The beam to the NU was delivered at 140 to 150 kW in March. By 
shortening the cycle time from 2.8 to 2.6 seconds, the beam power 
was increased to 170 to 180 kW. In addition, 200 kW user operation to 
the MLF was started by increasing pulse length on March 15.
     The J-PARC accelerator facilities have been operating  
successfully until March 22, however, operation stopped at 4:10 am 
by the trouble of the linac klystron power supply. The cause was due 
to the diode breakdown in the high voltage transformation unit. 
Finally, we replaced the transformation unit and the user operation 
to the MLF and the NU was resumed on April 8. Because the user 
program was stopped by this trouble for more than two weeks, the 
operation schedule in the 2012 fiscal year was modified to reduce 
this influence.

 A-TAC (ACCELERATOR ADVISORY COMMITTEE) MEETING  
     
     The 11th A-TAC (Accelerator Technical Advisory Committee) was 
held at Ibaraki Quantum Beam Research Center on February 23 to 25. 
Eight committee members attended and about 20 reports were presented 
such as the recovery from the earthquake, current situation, 
performance upgrade, etc. The committee deliberated and argued about 
the improvement points, future directivity, etc., and advice and 
recommendations were received from the committee.


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3. [Nuclear and Particle Physics Division] by M. NARUKI & T.TSUKAMOTO
----------------------------------------------------------------------

 SLOW EXTRACTION RESUMES AFTER EARTHQUAKE (by M. NARUKI)

     The slow extraction resumed at the end of January 2012 after the 
recovery work. The primary beam has been successfully extracted to 
the Hadron Hall and transported into the beam dump. The typical beam 
power was 3.3kW. The new Pt production target with the indirect water-
cooling system was successfully operated to find that it coped with 
the beam intensity of 30kW.
     The secondary particles were delivered to the K1.8, K1.8BR and KL 
beam lines. The E19 experiment searched for the Theta+ pentaquark in 
the p(pi-,K-)X reaction with the maximum momentum of 2 GeV/c at K1.8.
They accumulated the beam pions of 8.7x10^10 to reach the sensitivity 
of 0.3 micro-barn/sr. All the detector components worked well, and 
especially the beam tracking devices were able to operate stably 
under the typical intensity of 1.7M/spill with improved duty factor 
of 18%.
     At the K1.8BR area, beam tuning of 1.0 GeV/c for the E15 
experiment (kaonic-nuclei search) was successfully completed; the 
obtained yield of 1.0 GeV/c K- was 10k/spill/1kW with good K/pi 
ratio of 0.4. In addition, the commissioning of the cylindrical 
detector system (CDS) was conducted with a liquid-4He target in order 
to study the background to the kaonic-nuclei search. Target images 
and invariant mass of Lambda -> ppi- have been successfully 
reconstructed by the CDS in the preliminary results.
     The KOTO group performed a detector study to establish the 
calibration method for the electromagnetic calorimeter at the KL 
beam line. They successfully accumulated the events of neutral 
kaons decaying into charged pion, electron, neutrino and into 
three neutral pions. The next beam time for the Hadron Hall is 
expected in June.

 T2K STATUS: STABLE DATA TAKING RESTARTED AFTER 1 YEAR OF RECOVERY 
FROM THE EARTHQUAKE (by T.TSUKAMOTO)

     As reported in the previous issue of J-PARC newsletter, a 
serious trouble in the horn power supply arose on December 22 
during final operation test. Switching devices called IGBTs in the 
horn power supply were broken.
     Since it turned out that it takes a few months to get new IGBTs, 
we decided to use the old horn power supply which had been used until 
June, 2010 and was moved to KEK Tsukuba campus. Everything was 
finished in time for the beam but unfortunately a trouble of 
thyristor arose. We lowered the horn operation current from 250kA to 
200kA for safety until we will investigate the cause and fix it.
We are also working to repair the new power supply. Detailed checks 
for repair are being performed.
     We confirmed with use of beams that the alignment of magnets etc. 
in the neutrino beam line is OK, which were re-aligned after the 
earthquake. Beam tuning was carried out and the beam power reached 
150kW which is almost the same as before the earthquake.
     The commissioning of the neutrino beam has been successfully 
carried out and the T2K experiment has started normal data 
acquisition and collected data for the delivered POT (proton on 
target) is 2.19 x 10^19 in this beam run #41 (by the end of March).


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4. [Materials and Life Science Division] by Masatoshi ARAI
----------------------------------------------------------------------

 RESUMING USER OPERATION

 1. Neutron Source

     The conventional facilities resumed for beam operation without 
any serious problems. The first proton beam pulse was successfully 
transported from the RCS to the MLF target with an initial magnet 
setting. Then the beam line was tuned and optimized to the operation 
for user programs. The beam power was started with 100 kW and raised 
to 200 kW to recover the previous power right before the disaster in 
the middle of March.
     A helium gas purification unit was newly installed to the 
cryogenic hydrogen system in order to drastically reduce a problem 
from adsorbed moisture caused in 2011 in parallel with restoration 
work.  This upgrading solved an impurity issue of the system, and 
made the system operation in this winter much more stable.
     The surface roughness of the PIE (Post Irradiation Examination) 
specimens cut out from the first target was measured and the maximum 
pit depth of ca. 250 micro meter was found, which will be the 
important data to estimate the target vessel lifetime. The 2nd target 
vessel has been working without any troubles.

 EIGHTEEN NEUTRON INSTRUMENTS INCLUDING SIX NEW ONES HAVE BEEN 
STARTED

 2. Neutron Science

     Eighteen neutron instruments were successfully started.  Six new 
instruments are DNA (BL02, Inverted Geometry Spectrometer), SPICA 
(BL09, Powder), PLANET (BL11, High Pressure Diffractometer), TAIKAN 
(BL15, Small Angle Neutron Scattering), SHARAKU (BL17, Vertical 
Reflectometer) and SENJU (BL18, Single Crystal Diffractometer).
     For the user operation of the 2012A period (April to November, 
2012), 127 general neutron proposals have been submitted; after 
evaluation by four referees for each proposal followed by the review 
in the neutron science proposal review committee (NSPRC) held on March 
1st, 100 proposals were approved and 18 were reserved.  The results 
were approved by the MLF advisory board on March 13th.

 QENS2012/WINS2012

     Nikko Joint Conference between 10th International Conference 
on Quasielastic Neutron Scattering (QENS 2012) & 5th Workshop on 
Inelastic Neutron Spectrometer (WINS2012) will be held in Nikko 
Public Meeting Hall from 30th Sep. to 4th Oct. which is hosted by 
J-PARC Center with achair of Masatoshi Arai, MLF Division Leader. 
http://j-parc.jp/researcher/MatLife/en/meetings/QENS-WINS2012/
index.html


 COMMISSIONING OF NEW DETECTORS

 3. Neutron Instrument

     New types of a two-dimensional large area scintillator detector 
and a two-dimensional multi-wire proportional chamber with individual 
readout system have been successfully developed for BL18, SENJU, and 
BL17, SHARAKU. 
     The scintillator detectors with 33 modules were made based on 
the scintillator/wavelength shifting fiber technology. These were 
delivered to the beamlines by the end of March and the detector 
commissioning is currently underway.

 THE REGULAR USERS' PROGRAM AT MUSE WERE RESTARTED FROM FEB. 2ND, 
2012

 4. Muon Science Facility (MUSE)

     We managed to recover from all the damage induced by the 
earthquake on March 11th, 2011 by the end of December, 2011.
     It is our great pleasure to report we could deliver again, 
surface & decay muons up to 60 MeV/c beam towards D1 and D2 in the 
commissioning beam time held at Jan. 17th, 2012. The regular users of 
experiments were also restarted from Feb. 2nd.
     During a period of fixing, we installed a kicker magnet 
associated with a septum magnet to allow a single bunched muon beam 
cut out from the two bunched structure up to 60 MeV/c towards D1 and 
D2 areas in the MUSE secondary Decay-Surface Muon Beamline (D-line). 
It worked well, but it turned out we need further R&D in order to 
reduce noise signals that appeared in the Muon Spin Rotation, 
Relaxation and Resonance (muSR) spectrum.

----------------------------------------------------------------------
5. [Exotic Nuclear Science Group] by Y. HIRAHARA and Y.X. WATANABE 
----------------------------------------------------------------------

 SELECTIVELY IONIZED ATOMS EXTRACTED AT KISS (by Y. HIRAYAMA)

     We have been constructing the KEK Isotope Separation System 
(KISS) at RIKEN to study unexplored neutron-rich isotopes with 
neutron number N=126 for astrophysical interest. Using the KISS, 
isotopes of interest are produced by nuclear reactions and collected 
in a gas-cell filled with the argon gas. At the exit of the gas-cell, 
isotopes as neutral atoms are ionized by applying the laser resonant 
ionization technique. The selectively ionized atoms are then mass-
separated.
     As an offline test, neutral atoms of nickel evaporated from a 
filament inside the gas-cell were selectively ionized and extracted 
as nickel ion-beams at the KISS.

 CROSS SECTION MEASUREMENTS WERE PERFORMED FOR MULTI-NUCLEON TRANSFER 
REACTIONS (by Y.X. WATANABE)
     
     Neutron-rich nuclei around neutron number of 126, which are 
expected to be difficult for production by the uranium fission, will 
be synthesized as TLF's (target-like fragments) of multi-nucleon 
transfer reactions between a Pt-198 target and a Xe-136 beam of 
around 8 MeV/nucleon at the KISS project.
     In order to estimate the yields, we have performed an experiment 
at GANIL (Grand Accelerateur National d'Ions Lourds) to measure the 
cross-sections of PLF's (projectile-like fragments) produced by the 
reactions.
     The PLF's were clearly separated and collected by the VAMOS 
(variable mode high acceptance spectrometer), and gamma-rays emitted 
from TLF's as well as PLF's were simultaneously detected. Detailed 
analysis is in progress.


----------------------------------------------------------------------
6. [Nuclear Transmutation Section] by Hiroyuki OIGAWA
----------------------------------------------------------------------

 INTERNATIONAL SYMPOSIUM ON FUTURE OF ACCELERATOR DRIVEN SYSTEM WAS 
ORGANIZED

     The International Symposium on Future of Accelerator Driven 
System (ADS) was held on Feb. 29th, 2012 at Gakushi-kaikan, Tokyo, 
hosted by J-PARC Center and Nuclear Science and Engineering 
Directorate of JAEA. The objectives of this symposium are to discuss 
the role of ADS in the future nuclear utilization and to make 
participants acquainted with the current status and future plans for 
research and development of ADS in the world. There were about 100 
participants. At the beginning of the symposium, Dr. Arima, former 
Minister of Education, provided a special talk about the expectation 
for transmutation technology.  In the general sessions, current 
activities and future plans for R&D of ADS were presented from Japan, 
China, Korea, India, and Belgium. There were presentations for 
future plans of nuclear utilization and the role of partitioning and 
transmutation in Japan and Europe. After these presentations, a panel 
discussion was organized with regard to the prospective international 
collaboration and multidisciplinary synergy effect. Through the 
discussion, common understanding was promoted concerning the 
importance of international collaboration and appropriate sharing.


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7. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
----------------------------------------------------------------------

 THE SAFETY INSPECTIONS OF MLF AND HD WERE SUCCESSFULLY CONDUCTED BY 
NUSTEC

     The inspection of the Materials and Life Science Experimental
Facility (MLF) was conducted successfully on Feb. 6,7 by the Nuclear 
Safety Technology Center (NUSTEC): the inspection items were working 
conditions of emergency and interlock signals from the new secondary 
beam lines and shielding structures and measurements of ambient 
doses around the radiation control areas.
     The inspection of the Hadron Experimental Facility (HD) was 
conducted successfully on Feb. 21, 2012, by the NUSTEC: the 
inspection items were shielding structures and measurements of 
ambient doses around the radiation control areas.


----------------------------------------------------------------------
8. [Announcement of Symposia and Meetings]
----------------------------------------------------------------------

 1) Nikko Joint Conference between 10th International Conference on 
Quasielastic Neutron Scattering (QENS 2012) & 5th Workshop on 
Inelastic Neutron Spectrometers (WINS 2012), Sep. 30th - Oct. 4th, 
2012, Nikko, Japan (Language: English)
http://j-parc.jp/researcher/MatLife/en/meetings/QENS-WINS2012/index.
html


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9. [Editorial Note]
----------------------------------------------------------------------

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+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto at kek.jp
Nobuaki TAKAHASHI: nobuaki.takahashi at j-parc.jp
Takashi ITO: itou.takashi at jaea.go.jp
Dick MISCHKE (English Editor): mischke at triumf.ca
Toshiko MACHIDA (Secretary): machida.toshiko at jaea.go.jp
++++++++++++++++End of Letter++++++++++++++++++++++++++++++++++++++++++




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